1. Field of the Invention
The present invention relates to a cleaning mechanism, an image forming apparatus and an image forming system. Such an image forming apparatus may be embodied, for example, as an electrophotographic copying machine, a laser beam printer, an LED printer, a word processor, a facsimile or the like.
2. Related Background Art
In order to explain the background of the present invention, an image forming arrangement of a typical copying machine is shown in FIG. 13. In this arrangement, recording members (recording media) 52 are stacked on a stacking plate 51 pivotally mounted on a pin 50, which stacking plate is biased toward a supply roller 54 so that the stacked recording members 52 are abutted against the supply roller. When the supply roller 54 is rotated, only an uppermost recording member 52 is separated from the other recording members by a friction pad 55 biased toward the supply roller 54 and is fed to a pair of regist rollers 56a, 56b which in turn feed the recording member to a process cartridge 57 constituting an image forming station. The process cartridge 57 serves to uniformly charge a surface of a photosensitive drum (image bearing member) 57a by a charger 57b, form a latent image on the photosensitive drum by selectively exposing the latter and develop the latent image with toner by a developing device 57c. The toner image is transferred onto the recording member 52 to form an image on the latter. Therefore, the recording member 52 is sent to a fixing device (not shown) where the toner image is fixed to the recording member. Then, the recording member is ejected out of the copying machine.
After the transferring operation, the residual toner remaining on the photosensitive drum 57a is removed by a cleaning device 57d. As shown in FIG. 14, the cleaning device 57d comprises a cleaning blade 57d1 for scraping the residual toner on the photosensitive drum 57a, and a dip sheet 57d2 for receiving the scraped toner and for sending it to a cleaning container 57d3. Incidentally, the dip sheet 57d2 comprises a thin elastic sheet and is lightly contacted with the peripheral surface of the photosensitive drum 57a so as to permit the passage of the residual toner on the photosensitive drum 57a but direct the toner scraped by the blade 57d1 to the container 57d3.
Further, the cleaning device 57d has partition walls 57d4 which extend to a direction perpendicular to a rotation axis 57a1 of the photosensitive drum 57a as shown by the alternate long and short dash line in FIG. 15 and serve to divide the cleaning container 57d3 into a plurality of chambers so that the waste toner collected from leaking from the container 57d3 due to the offset of the waste toner. Incidentally, regarding this technique, the effective invention has been proposed by the inventors as disclosed in U.S. Pat. No. 4,530,594.
As mentioned above, in the cleaning container 57d the interior of which is divided into a plurality of chambers by the partition walls 57d4, each partition wall has a thickness T and, as shown in FIG. 14, free ends of the partition walls are spaced apart from the photosensitive drum 57a by a small gap L (about 1 mm-3 mm). Consequently, small spaces V each having a volume of T.times.L are formed at an end of the cleaning container where the partition walls 57d4 confront to the photosensitive drum 57a.
Further, as shown in FIG. 16, the small spaces V (hatched portions shown in FIG. 16) are aligned with or confronted to an area where the supply roller 54 and the friction pad 55 are contacted with the recording member 52 and an area where the paired regist rollers 56a, 56b are contacted with the recording member in a recording member convey direction. In such a case, paper powder generated when a recording paper sheet as the recording member 52 passes between the supply roller 54 and the friction pad 55 and between the paired regist rollers 56a, 56b is sent to the image forming station together with the recording member 52. Then, the paper powder goes along the photosensitive drum 57a and is coagulated together with the residual toner, thereby sometimes filling the small spaces V. As a result, it is feared that the residual toner cannot be collected effectively, with the result that the toner may spill from the cleaning container 57d3.
Further, when the recording member 52 is conveyed by the supply roller 54 and/or the paired regist rollers 56a, 56b, as shown in FIG. 17, the paired regist rollers 56a, 56b are flexed or deflected in accordance with the thickness of the recording member 52, with the result that the contacting pressure between the recording member 52 and the regist rollers at both ends 52a, 52b of the recording member sometimes becomes greater than that at a central portion of the recording member. As a result, the both ends 52a, 52b of the recording member 52 become particularly nappy and the paper powder is greatly generated at the both ends of the recording member. Further, other than by the contacting pressure of the rollers, the both ends 52a, 52b of the recording member 52 are apt to become nappy due to the cutting of the recording member, and thus, when the both ends of the recording member are contacted with the convey guide and the like, the both ends of the recording member become more nappy and a larger amount of paper powder is generated.
By the way, recently, in order to use resources on the earth effectively, corrugated cardboards, newspapers and/or waste copied paper sheets have been re-cycled to obtain regenerated paper sheets for use as recording members 52. The regenerated paper sheets generally have paper fibers shorter than those in the recording members which are not made from the regenerated paper sheets, and thus, are apt to become happy and generate paper powder. The generated paper powder is apt to be coagulated, and particularly, is apt to form the condensation. As a result, it is still feared that the small spaces V of the cleaning container 57d3 will be filled with coagulated.
Incidentally, some cleaning devices have a mechanism for forcibly feeding the waste toner collected in the cleaning container 57d3 into the interior of the container. In such cleaning devices, since the collected waste toner is forcibly fed into the interior of the cleaning container, the possibility that the small spaces V are filled with the toner is reduced. However, for example, as shown in FIG. 18, since the toner feeding mechanism forcibly feeds the toner by rotating a feed vane 58a in a direction shown by the arrow, it is necessary to provide the feed vane 58a, a gear 58b attached to a rotary shaft of the feed vane 58a to rotate the latter, and an idler gear 58c for transmitting a driving force from a photosensitive drum gear 59 to the gear 58b.
Further, nowadays, process cartridges each incorporating therein a photosensitive drum 57a, cleaning device 57d and the like as a unit which can be removably mounted within an image forming apparatus thereby to facilitate the supply of toner and the maintenance have been used. It has been desired to make such process cartridges small-sized and to reduce the cost of the process cartridges. Accordingly, if the above-mentioned toner feeding mechanism is provided in the cleaning device 57d, the number of parts will be increased to result in an increased cost and the toner feeding mechanism will require an additional space, thus preventing the compactness of the process cartridge.